我的API使用Jersey 2，现在我想支持国际化。我知道客户端应该指定Accept-Language参数，但我想了解如何正确处理它。
假设我的API只能处理FRENCH和ENGLISH两种语言。我知道可以使用以下代码检索首选区域设置：
@GET
@Path("a-path")
public Response doSomething(@Context HttpServletRequest request) {
Locale locale = request.getLocale();
// ...
}
Accept-Language: da, en-gb;q=0.8, en;q=0.7，根据w3c，它基本上意味着：“我喜欢丹麦语，但也可以接受英国英语和其他类型的英语。”。由于首选语言仅返回最符合预期的语言环境，有没有一种方法可以选择我的API支持的第一种语言呢？我想在一个地方（即 Filters ）处理它，而不是在每个资源中进行处理。获取语言环境的一种方法是使用 HttpHeaders#getAcceptableLanguages()。
获取响应中可接受的语言列表。
如果未指定可接受的语言，则返回一个只读列表，其中包含一个带有“*”语言字段的通配符Locale实例。
返回：按其q值排序的可接受语言的只读列表，首选项最高。
您可以在几乎任何地方注入HttpHeaders，使用@Context
public Response doSomething(@Context HttpHeaders headers) {
List<Locale> langs = headers.getAcceptableLanguages();
ContainerRequestContext获取区域设置列表。@Override
public void filter(ContainerRequestContext requestContext) throw .. {
List<Locales> langs = requestContext.getAcceptableLanguages();
}
Locale，但不想在方法中进行所有区域设置的"解析"，你可以使用一些依赖注入，并创建一个Factory，在那里你可以注入HttpHeaders并在那里解析语言环境。Factory，这样你就可以将已解决的Locale注入到资源方法中。该示例使用一个虚拟的语言环境解析器，只允许英语。在我们解析语言环境之后，我们将其设置为请求上下文属性，并从Factory内检索，以便我们可以将其注入到资源方法中。@GET
public String get(@Context Locale locale) {
return locale.toString();
}
另请参阅: 如何将对象注入Jersey请求上下文？
如果您需要我解释示例的其他内容，请告诉我。
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import java.util.logging.Logger;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.container.PreMatching;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.Provider;
import org.glassfish.hk2.api.Factory;
import org.glassfish.hk2.utilities.binding.AbstractBinder;
import org.glassfish.jersey.filter.LoggingFilter;
import org.glassfish.jersey.process.internal.RequestScoped;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
/**
* Stack Overflow question https://dev59.com/x5bfa4cB1Zd3GeqPuHmB
*
* Run this like any other JUnit test. Only one required test dependency:
*
* <dependency>
* <groupId>org.glassfish.jersey.test-framework.providers</groupId>
* <artifactId>jersey-test-framework-provider-inmemory</artifactId>
* <version>${jersey2.version}</version>
* </dependency>
*
* @author Paul Samsotha
*/
public class AcceptLanguageTest extends JerseyTest {
@Path("language")
public static class TestResource {
@GET
public String get(@Context Locale locale) {
return locale.toString();
}
}
public static interface LocaleResolver {
Locale resolveLocale(List<Locale> locales);
}
// Note: if you look in the javadoc for getAcceptableLanguages()
// you will notice that it says if there is not acceptable language
// specified, that there is a default single wildcard (*) locale.
// So this implementation sucks, as it doesn't check for that.
// You will want to make sure to do so!
public static class DefaultLocaleResolver implements LocaleResolver {
@Override
public Locale resolveLocale(List<Locale> locales) {
if (locales.contains(Locale.ENGLISH)) {
return Locale.ENGLISH;
}
return null;
}
}
@Provider
@PreMatching
public static class LocaleResolverFilter implements ContainerRequestFilter {
static final String LOCALE_PROPERTY = "LocaleResolverFilter.localProperty";
@Inject
private LocaleResolver localeResolver;
@Override
public void filter(ContainerRequestContext context) throws IOException {
List<Locale> locales = context.getAcceptableLanguages();
Locale locale = localeResolver.resolveLocale(locales);
if (locale == null) {
context.abortWith(Response.status(Response.Status.NOT_ACCEPTABLE).build());
return;
}
context.setProperty(LOCALE_PROPERTY, locale);
}
}
public static class LocaleFactory implements Factory<Locale> {
@Context
private ContainerRequestContext context;
@Override
public Locale provide() {
return (Locale) context.getProperty(LocaleResolverFilter.LOCALE_PROPERTY);
}
@Override
public void dispose(Locale l) {}
}
@Override
public ResourceConfig configure() {
return new ResourceConfig(TestResource.class)
.register(LocaleResolverFilter.class)
.register(new AbstractBinder() {
@Override
protected void configure() {
bindFactory(LocaleFactory.class)
.to(Locale.class).in(RequestScoped.class);
bind(DefaultLocaleResolver.class)
.to(LocaleResolver.class).in(Singleton.class);
}
})
.register(new LoggingFilter(Logger.getAnonymousLogger(), true));
}
@Test
public void shouldReturnEnglish() {
final String accept = "da, en-gb;q=0.8, en;q=0.7";
final Response response = target("language").request()
.acceptLanguage(accept)
.get();
assertThat(response.readEntity(String.class), is("en"));
}
@Test
public void shouldReturnNotAcceptable() {
final String accept = "da";
final Response response = target("language").request()
.acceptLanguage(accept)
.get();
assertThat(response.getStatus(), is(Response.Status.NOT_ACCEPTABLE.getStatusCode()));
}
}
import javax.ws.rs.core.Variant;
import javax.ws.rs.core.Request;
@Context
private Request req;
private Locale getResponseLocale(boolean throwIfNoneMatch) throws NotAcceptableException{
// Put your supported languages here
List<Variant> langVariants = Variant.languages(
new Locale("da"),
new Locale("en-gb"),
Locale.getDefault()).build();
Locale locale = Locale.getDefault();
Variant selectVariant = this.req.selectVariant(langVariants);
if (selectVariant != null) {
locale = selectVariant.getLanguage();
} else if (throwIfNoneMatch) {
throw new NotAcceptableException(Response.notAcceptable(langVariants).build());
}
return locale;
}
另请参阅Java EE教程：运行时内容协商。